code: def _docstring_extra(extra_docs):
      return "" if extra_docs is None else extra_docs
  
file_path: bokeh/src/bokeh/plotting/_docstring.py
imports: from __future__ import annotations
  import logging
  from inspect import Parameter
  from ..models import Marker
label_desc: Use image node_id 4 for calling a global function with example usage: _docstring_extra(extra_docs) and returns: unknown